Electronic devices often include connectors to provide ports where power and data signals can be shared with other devices. These connectors are often designed to be compliant with a standard, such that the electronic devices can communicate with each other in a reliable manner. The various Universal Serial Bus (USB), Peripheral Component Interconnect Express (PCIe), and DisplayPort (DP) standards are but a few examples.
On occasion, the standards that use these connectors are replaced by newer standards. As a result, multiple connectors that provide similar functions are often included on an electronic device. For example, many current televisions include inputs for HDMI, S-video, component video, and RCA jacks.
The inclusion of these connectors increases device size, complexity, and cost. Also, the inclusion of several options can cause confusion and frustration for customers as they try to determine the best way to configure a particular system.
Some of this confusion could be reduced if one connector was able to provide signals for more than one standard. For example, if one connector could provide signals for both a legacy standard and a newer standard, the number of connectors on an electronic device could be reduced, thereby enabling the device to be made smaller, simpler, and less expensive.
But as helpful as this would be, it is very difficult to do. For example, circuits associated with one standard may interfere with circuits associated with another standard. This becomes even more difficult when data rates are high, as reflections and termination mismatches caused by unused circuits impair the performance of the circuits being used.
For example, a newer, faster standard may share a connector with a legacy, slower standard. Circuitry necessary for the legacy standard may cause reflections and termination mismatches for the circuits for the newer, faster standard, thereby degrading system performance.
Thus, what is needed are circuits, methods, and apparatus that allow various standards to share a common connector.